What determines the element count for vxor.vv?
The current vl and vtype determine it, with vstart, LMUL, SEW, mask state, and tail policy also affecting execution.
VXOR.VV
RISC-V VXOR.VV Instruction Details
Instruction ManualR-typeVXOR.VV performs bitwise XOR on vector elements.
Instruction Syntax
vxor.vv vd, vs2, vs1, vm
Operand Breakdown
Destination rd: register receiving the operation result.
Source rs1: register holding the first operand.
Source rs2: register holding the second operand.
VVector Operations
Instruction Behavior
vxor.vv is a V extension integer logical instruction that computes element-wise XOR between vs2 and vs1.
Quick Understanding & Search Notes
vxor.vv is a V extension vector instruction. Active elements are controlled by vl, vtype, vstart, and the optional v0.t mask; XOR is applied element-wise with vs2.
Official syntax is `vxor.vv vd, vs2, vs1, vm`; without a mask operand it is unmasked, while `, v0.t` updates only selected active elements.
Tail elements and masked-off elements follow the current vtype tail/mask policy; the mnemonic alone does not imply zeroing.
It does not set condition codes or produce a Boolean mask; the result is ordinary vector elements.
Common Usage Scenarios
Bit Operations & Masks
Understand this scenario with real code like «vxor.vv v8, v12, v4, v0.t».
Data Storing
Understand this scenario with real code like «vxor.vv v8, v12, v4, v0.t».
Vector Operations
Understand this scenario with real code like «vxor.vv v8, v12, v4, v0.t».
Pre-Use Checklist
Syntax Check
- Confirm the current instruction format is R-type.
- Confirm the operand order matches the example.
Semantic Check
- Ensure the destination register usage is compatible with the calling convention.
- Confirm this is not the lower-level form of a pseudo-instruction expansion.
Pitfalls / Common Confusions
XOR is a bitwise logical operation; signedness does not affect comparison magnitude because there is no comparison.
The result width is SEW; this is not a widening operation.
Masked-off and tail elements follow the current policy.
FAQ
Does vxor.vv always process the whole vector register?
No. V instructions operate on active elements; register grouping and inactive-element behavior are controlled by vtype and policy bits.